An adhesive is a substance capable of holding solid materials (e.g., adherents or substrates) together by surface attachment. Pressure sensitive adhesives (PSAs) generally are adhesive materials which bond to adherents when a required pressure is applied to effect an adhesion to the adherents. PSAs can be permanent or removable. Removable PSAs have been widely used in re-positionable applications, such as POST-IT notes. PSAs are also employed to facilitate the bonding of flooring tiles and carpets to the ground, packaging, posters, labeling upon various substrates, road signs, and the like.
Pressure sensitive adhesives are generally based on a polymer, a tackifier and an oil. Some common PSAs are based on polymers such as natural rubbers, synthetic rubbers (e.g., styrene-butadiene rubber (SBR) and SIS), polyacrylates, polymethacrylates, and poly-alpha-olefins. The PSAs can be solvent-based, water-based, or hot melt systems.
Despite the research efforts in developing pressure sensitive adhesive compositions, there is still a need for a pressure sensitive adhesive composition with improved balance of properties such as shear adhesion, loop tack, and peel strength.